Looper-operating mechanism for sewing machines and thread controls for the looper



worn OPERATING ucnmxsu FOR sauna ucnmas MMM V A. J. WOHLPART 7 AND THREAD CONTROLS FOR THE LObPBR Fi lod Jan. 11, 192'! 4 Sheets-Sheet 2 w &1 (D ---T 1,699,262 A. J. WOHLPART me MECHANISM FOR snwmp MACHINES Jan. 15, 1929.

LOOPER OPBRAT AND THREAD CONTROLS R THE LOOPBR V 4 Sheets-Sheet 4 Filed ,Jan- 11.

Patented Jan. 15, 1929.

UNITED STATES 4 A 1,699,262 PATENT OFFICE.

AUGUST J. WOHLPABT, 01' NEW YORK, N. Y., ASSIGNOB TO UNION SPEGJLAL IAOHINI COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLIII'OIQ.

LOOPEB-OPEBATING MECHANISH.FOB SEWING MACHINES AITD THREAD FOR THE LOOPER.

CONTROL! Application m January 11, 1927. semi No. 10am.

The invention relates to new and useful improvements in sewing machines, and more particularly to a sewing machine having a thread carrying looper and the actuat ng mechanism therefor, and also. a control for the looper thread.

An object of the invention is to provide a looper operating mechanism for a sewing machine of the above type wherein the looper 1s oscillated positively from an actuating shaft located beneath the work support by a de pending member extending downwardly from the shaft and connected to a rock shaft which in turn oscillates the looper, and wherein the looper is moved laterally by a member extending downwardly from the actuating shaft and connected to an arm which is rigid with'the support for the looper.

A further object of the invention is to provide a looper operating mechanism of the above type wherein the depending member which oscillates the loo er has an arm rigidly attached thereto whic engages the looper thread passing through thread guides and takes up the looper thread at the proper time to insure the oint of the needle entering the thread triang e.

These and other objects will in part be obvious and will in part be hereinafter more fully described.

In the drawings which show by way of illustration one embodiment of the inven tion Figure 1 is a view partly in front elevation and partly in section showing a sewing machine embodying my improvements;

Fig. 2 is a view partly in plan and partly in section immediately above the work support with a portion of the work support broken away to show the parts beneath the same;

Fig. 3 is a sectional view on the line 33 of Fig. 2;

Fig. 4 is a sectional view on the line 4--4 of Fig. 1;

Fig. 5 is a sectional view on the l1ne5- -5 of Fig. 2;

Fig. 6 is I a diagrammatic view showing the position of the thread controlling arm when the looper is at the forward end of its stroke;

Fig.

7 is a'similar view but showing the thread controlling arm moving into engagemeat with the looper threadas the looper point begins its retracting movement;

Fig. 8 is a similar view but showing the s position of the thread controlling arm as the point of the needle is entering the thread triangle; and Fig. 9 is a similar View but showing the thread controlling arm aspositioned when the looper is at the rear end of its stroke. The invention is directed broadly to-a sewing machine having a thread carrying looper moving back and forth in a direction at right angles to the line of feed. The thread carrying looper is not only oscillated, but is given a lateral movement at each end of its stroke. The actuating shaft for the loo er is located beneath the work support, but is setwell up from the bed. The looper is carried by an arm which is pivoted to a looper sup ort. This arm is oscillated on the support by a link connection to a rock shaft. The rock shaft is mounted in lugs in the supporting bed of the machine and extends beneath the actuating shaft for the looper. The actuat ing shaft is provided with a crank. The rock shaft is provided with an arm which is located beneath the actuating shaft and a link connected to the crank is also connected to the end of this arm so that as the crank rotates the rock shaft is oscillated and the rock shaft will impart an oscillation to the looper. This link is in the form of an L-shaped e5 arm and the free end of the L-shaped arm engages the looper thread and is the controlling element therefor. The 100 or is moved laterally bly means of an arm w ich is attached to the ooper support. This arm extends to a point directly under the actuating shaft and is connected to an eccentric stratp cooperating with an eccentric on the sha t. 1 y

Referring more in detail to the drawings my invention ,resides in. a sewing machine having a supporting bed 1 carrying a standard 2 having an overhanging arm 3 in which a needle bar 4 reciprocates. The main shaft 5 is mounted in the overhanging arm and is actuated by a belt wheel 6. I Mounted on the bed 1 is a front bracket 7 and a rear bracket 8. The work support 9 is mounted ,on these brackets. Coo rating with the needle carried by the nee e bar 4 ml is a thread carrying looper 10. This looper,

so i

shaft which is rotated by suitable connecof the needle thread loop.

The looper thread is led from the supply is mounted insuitable bearings 19 carried by I arm 24 which likewise extends underneath the neaaaea 10 is mounted in a carrier 11 which in turn is mounted to oscillate on a supporting stud 12 carried by and projecting laterally from a looper support 13. The looper carrier 11 is oscillated on the stud 12 by a link 14 which is pivoted at 15 to the carrier, and is also pivoted at 16 to an upstanding arm 17 rigidl connected to a rock shaft 18. This rock sha t indicated at 1 in the drawings, passes through first the thread guide 35 and thence the thread guide 36 and from the thread guide 36 the looper thread passes to the looper.

When the looper is at the forward end of its stroke the crank 22 is at the extreme upper point in its path of rotation (see. Fig. 6). The ball stud 12 on the end of the arm which moves the rock shaft is also at the extreme upper point of its oscillation. At this time the thread controlling arm is substantially horizontal and is well above the thread guides 35 and 36 and the looper thread 1 passing therethrough. As the crank continues its rotation it will impart very little retracting movement to the looper until the parts reach the position indicated diagrammatically in Fig. 7 The arm of the crank however moving from the position shown in Fig. 6 to the position shown in Fig. 7 has caused the L- shaped arm of which the looper controlling arm is a part to have taken an angular position and broughtthe recess 31 in the controlling arm 27 down into engagement with the the bed plate 1.

Beneath the work support 9 is an actuating tions with the main shaft 5. This shaft 20 isjournaled in the front and rear-brackets 7 and 8 and is located at some distance above the bed plate 1. The rock shaft 18 extends beneath the actuating shaft 20 and is provided at its inner end with an arm 21 (see Fig. 3). Theactuating shaft 20 is provided with a crank 22. A link 23 cooperates with the crank and is connected to a ball stud on the end of the arm 21. When the main shaft 20 rotates it will oscillate the rock shaft 18 and the oscillations ofthe rock shaft 18 will be imparted to the looper carrier 11 and thus move the looper back and forth into and out movement to the position shown in Fig. 8. the controlling arm engages the thread and pulls on the thread so as to take up the slack accumulating in the looper thread as the looper retracts. The urpose of taking up the slack at this time is to cause the thread running from the eye of the looper to the previous stitch to be free from slack and substantially taut at the time when the point of the needle is entering the thread triangle. As the crank continues its movement to the position shown in Fig. 9, the looper continues its retracting movement to the rear end of its stroke. At the same time the thread controlling arm has again assumed a horizontal position. The thread controlling arm as the crank continues its movement gives up slack to the looper thread and is entirely free from engagement with the looper thread when the looper is entering the needle thread loop and drawing on the looper thread. If the looper The looper support 13 is provided with an shaft 20 and terminates directly beneath the shaft. The shaft 20 carries an eccentric 25. An eccentric strap 26 cooperates with the eccentric 25 and is connected to a ball stud on the end of the arm 24. The rotations of the shaft 20 through the eccentric 25 will oscillate the looper support 13 and thus impart a lateral or needle avoiding movement to the looper. The link 23 is provided at its end where it co-operates with the crank with an arm 26, which extends in a direction substantially at right angles to the longitudinal axis of the link. Mounted on the end of the arm 26 is the thread controlling arm 27 for the looper thread. This arm 27 is provided with a recess 28 which receives the end of the arm 26. The arm 27 is also provided with a slot 29 and thread passes out of the recess 31 it will be a screw 30 passing through the slot secures retained by the downwardly bent portion at the controlling arm 27 to the actuating arm 26 the free end of the arm and will slide back therefor. This slotted\connection permits the along the arm into the recess. thread controlling arm to be adjusted radially ii The machine is provided with a 'throat Hplate 38 of the usual type. The material is fed across the work support by a feed dog 39 carried by a feed bar 40, which is pivoted to a feed rocker 41. The feed rocker is oscillated by an arm 42. which is connected by a link to a crank on the end of the actuating shaft 20. The feed bar 40 is provided with a downwardly and forwardly projecting arm 43 which extends beneath the actuating shaft 20. There is an eccentric on the shaft 20 and toward and from the tenter of the actuating shaft 20. The threadicontrolling arm 27 is shaped so as to provide a U-shaped recess 31 on the under ftlC B'thGIGOf. Fhis is back from the end of the arm and the end of the arm is bent downwardly at substantially right angles to the longitudinal center of the arm;

through a thread guide 32, thence to a thread guide 33 from which the looper thread is led to a thread guide 34. Associated with the arm 27 are two thread guides 35 and 36, one on each side of the plane of movement of the free end of said arm. The looper thread,

is connected to-the free end of the member 43 and thus it is that the feed dog is raised and lowered. This feeding mechanism forms no looper thread. As the crank continues its an eccentric'strap 44 cooperating therewith angles to the main shaft, an arm carried by part of the invention, but is shown, described and claimed in my coending application, Serial No. 160,432, filed of even date herewit From the above it will be apparent that I have provided a sewing machine wherein the actuating shaft beneath the work support is set Well up from the bed so that the looper actuating parts may be mounted close to the bed and the looper oscillates by a member extending downwardly in a substantially vertical direction from the actuating shaft therefor. Likewise the looper is moved laterally from an actuating member extending downwardly from the actuating shaft in a substantially vertical direction. The feed dog is raised and lowered by a member extending downwardly from this actuating shaft. The control for the looper thread is a part of and derives its movements from this downwardly extending 'member which oscillates the looper. This all contributes to a very simple mechanism which may be driven at a very high speed and be free from excessive vibration.

It is obvious that minor changes in details of construction may be made without departing from the spirit of the invention as set forth in the appended claims.

What I claim as new is a 1. The combination of a thread carrying looper, a carrier therefor,a supporting shaft on-which said carrier is mounted for oscillation, a main actuating shaft parallel to said first named shaft .and disposedat one side thereof, said first named shaft having an arm projecting beneath said main shaft, an eccentric member located on said main shaft directly above the'free end of said arm and connected thereto for imparting oscillations to the shaft and a needle avoiding movement to the looper, a rock shaft disposed at right the rock shaft and connected to the looper carrier for oscillating the looper into and out of the needle thread loop, said rock shaft having an arm located directly beneath the main shaft, and means on the main shaft connected to said arm for oscillating the rock shaft.

2. The combination of a thread carrying looper, a carrier therefor, an actuating shaft, and means operated by said shaft for oscillating said looper carrier including a rock shaft extending beneath said actuating shaft and provided with an arm disposed directly under the shaft, a crank on the actuating shaft, and a link connected to said crank and to said arm for oscillating therock shaft, an arm rigidl connected to said link at the end thereof ad acent the crank and extendingat substantially ri ht angles to the length of the link, and threa guides associated with said arm through which the looper thread passes,

said thread guides being so disposed that said,

arm engages the thread and takes up the slack in the looper thread as the looper begins its retractin'g movement. j

3. The combination of a thread carrying looper, a carrier therefor, a supporting shaft on which said carrier is mounted for oscillation, a main actuating shaft disposed at one side of the looper shaft, said looper shaft having an arm projecting beneath the main actuatingshaft, an eccentric on said main actuating shaft, an eccentric strap cooperating therewith and connected to said arm, a rock shaft extendin substantially at right angles to the main shaft,.an arm carried by said rock shaft, a link connecting said arm to the looper carrier for oscillating the looper carrier, said rock shaft having an arm located beneath the main actuating shaft, a second eccentric on said main shaft, and an eccentric strap cooperating therewith and connected to the arm on the rock shaft for oscillating the rock shaft,

4. The combination of a support bed, a work support mounted thereon, an actuating shaft located. beneath the work support and above said bed, a rock shaft mounted in bearin lugs carried by the bed and disposed at su stantially right angles to the axis of the actuating shaft and looper, a 100 er carrier, a looper support on which sai carrier is pivoted, means for connecting the rock shaft to the looper carrier, an arm on the rock shaft directly beneath the actuating shaft, an eccentric member on said actuating shaft, 9. link cooperating with said eccentric member and connected to the free end of said arm for oscillating the rock shaft, an arm rigid with the support for the looper carrier having its free end terminating directly beneath the actuating shaft, an eccentric carried by said actuating shaft, an eccentric strap cooperating with said eccentric and connected to the arm carried by the looper support for oscillatingsaid looper support.

5. he combination of a thread carrying looper, a carrier therefor, an actuating shaft, means operated by said shaft for oscillating said looper including a rock shaft extending beneath the actuatin shaft and provided with an arm disposed directly beneath the said shaft, said actuating shaft having a crank, a link connected with the crank and cooperating with the free end of said rock shaft, an arm rigid with said link adjacent the crank and extending substantially at right cent its outer end for engaging the looper angles thereto, said arm having a recess adj athread, andthread guides associated with said arm.

In testimony whereof, I aflix signature. AUGUST J WOHLPART. 

